Otto Piene is a Germanâborn conceptual artist who focuses on both urban landscapes and wild, natural settings. In the late 1960s he coined the term âSky Artâ to refer to a series of projects that used the sky as his canvas. Using inflatable sculptures and the participation of dozens of volunteers and spectators, Piene demonstrated his concern with the spatial relationships between form and space. His Sky Art series, consisting of 25 potential scenarios for environmental art projects, marked the first time that Tamarind used photosensitized plates to create a lithograph. While Tamarind has been characterized as a strictly traditional workshop that used no photo-based processes, there were at least two instances in which artists incorporated photographs into their work. In this case, Piene had a negative made of a photograph, which was then exposed onto an aluminum plate at a local commercial printshop. The aluminum plate was then processed and printed at Tamarind.